Inkjet Ink System for Handling High Solid Particles Loaded Inks

Abstract

The application describes an ink delivery system for an inkjet printer. The system includes a first ink tank operative to supply ink to at least one inkjet printhead and a second ink tank operative to receive ink flown through at least one printhead and not used by at least one printhead. The ink for printing is drawn by low pressure from a first tank through the printhead to a second ink tank. Each of the ink tanks includes a cylindrical tubular segment and a segment with a frustoconical inner section.

1 - 26 . (canceled) 
     
     
         27 . An ink delivery system for an inkjet printer, comprising:
 a first ink tank operative to supply ink to at least one inkjet printhead;   a second ink tank operative to receive ink flowing through the at least one inkjet printhead and not used by said at least one inkjet printhead;   a negative pressure generator generating a negative pressure between said first ink tank and said second ink tank; wherein   a body of each of the first and the second ink tanks includes a cylindrical segment and a segment with frustoconical inner section; and wherein the ink for printing is drawn from the first ink tank through the printhead to the second ink tank.   
     
     
         28 . The ink delivery system of  claim 27 , wherein at least one of the first and second inks tank include:
 a minimum ink level sensor; and   a maximum ink level sensor.   
     
     
         29 . The ink delivery system of  claim 28 , wherein the minimum ink level sensor and the maximum ink level sensor are each independently selected from the group consisting of floating level sensors, magnetic reed switch-based floats, solid-state electro-optical switches, conductivity sensors, capacitive switched, ultrasonic switches, and piezo-resonant switches. 
     
     
         30 . The ink delivery system of  claim 27 , further comprising a pump, wherein the minimum level sensor activates said pump delivering ink from the second ink tank into the first ink tank. 
     
     
         31 . The ink delivery system of  claim 27 , wherein the first ink tank supplies ink to at least one printhead. 
     
     
         32 . The ink delivery system of  claim 27 , wherein each of the first and the second ink tanks include at least one ink sloshing reducing baffle. 
     
     
         33 . The ink delivery system of  claim 27 , wherein the cylindrical segment of the ink tank is rigidly coupled to the segment with frustoconical inner section of the ink tank. 
     
     
         34 . The ink delivery system of  claim 27 , further comprising at least one ink outlet; wherein
 the first ink tank operates to supply ink to the at least one inkjet printhead; and wherein   the first ink tank supplies ink through the at least one ink outlet located at a narrow part of the segment with frustoconical inner section.   
     
     
         35 . The ink delivery system of  claim 27 , further comprising at least one of an ink circulation system and an ink agitation system. 
     
     
         36 . The ink delivery system of  claim 27 , wherein the angle  150  of the frustoconical segment is from about 20 to about 160 degrees. 
     
     
         37 . The ink delivery system of  claim 27 , wherein a pressure differential draws the ink from the first ink tank through the printhead to the second ink tank. 
     
     
         38 . The ink delivery system of  claim 37 , wherein the pressure differential is a negative pressure of −0.05 to −0.5 bar that draws the ink from the first ink tank through the printhead to the second ink tank. 
     
     
         39 . The ink delivery system of  claim 27 , wherein
 at least one of the first and second ink tanks further comprise:
 a minimum ink level sensor; 
 a maximum ink level sensor; wherein
 the minimum ink level sensor and the maximum ink level sensor are each independently selected from the group consisting of floating level sensors, magnetic reed switch-based floats, solid-state electro-optical switches, conductivity sensors, capacitive switched, ultrasonic switches, and piezo-resonant switches; 
 
   and wherein the ink delivery system further comprises:
 a pump, wherein the minimum ink level sensor activates said pump to deliver ink from the second ink tank into the first ink tank; 
 at least one of an ink circulation system and an ink agitation system; and 
 at least one ink sloshing reducing baffle. 
   
     
     
         40 . A method of delivering ink to an inkjet printhead in an inkjet printing system, comprising:
 providing an inkjet printing system including a first ink tank, a second ink tank and at least one inkjet printhead; wherein
 at least one of the first and second ink tanks comprises a body including a cylindrical segment and a segment with frustoconical inner section; wherein 
 each ink tank further comprises a minimum ink level sensor and a maximum ink level sensor; wherein 
   the minimum ink level sensor operates a pump to transfer ink from the second ink tank into the first ink tank, and   generating a difference in pressure between the first and the second ink tank; wherein the difference in pressure draws ink from the first ink tank through the printhead to the second ink tank.   
     
     
         41 . The method of  claim 40 , wherein the maximum ink sensor level disposes of excess ink. 
     
     
         42 . The method of  claim 40 , further comprising employing a pressure generator operative to generate a pressure difference between the first and the second ink tanks. 
     
     
         43 . The method of  claim 40 , wherein the pressure difference is −0.05 to −0.5 bar, that draws the ink from the first ink tank through the printhead to the second ink tank. 
     
     
         44 . The method of  claim 40 , further comprising draining the ink delivery system through at least one of a drain channel of the first ink tank and an ink drain outlet of the second ink tank. 
     
     
         45 . The method of  claim 40 , wherein an ink includes at least 40% of solid particles. 
     
     
         46 . A method of circulating ink in an inkjet printing system, comprising:
 providing an inkjet printing system including a first ink tank, a second ink tank and at least one inkjet printhead;   generating a difference in pressure between the first and a second ink tanks and   wherein the difference in pressure draws ink from the first tank through the printhead to the second ink tank; wherein   the first and second ink tanks each have a body including a cylindrical segment and a segment with a frustoconical inner section; wherein
 each ink tank further includes a minimum ink level sensor and a maximum ink level sensor; and wherein 
 a minimum ink level sensor operates a pump which transfers ink from the second ink tank into the first ink tank.